EnsureFolderExists

    static class PathExtensions
    {
        public static string EnsureFolderExists(this string path)
        {
            if (string.IsNullOrEmpty(path))
                return path;

            string fullPath = Path.GetFullPath(path);

            if (!Directory.Exists(fullPath))
                Directory.CreateDirectory(fullPath);
            return fullPath;
        }
    }